/*
 * Copyright (c) 2014, 2017, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package com.oracle.svm.core.threadlocal;

import org.graalvm.nativeimage.Platform;
import org.graalvm.nativeimage.Platforms;
import org.graalvm.word.LocationIdentity;

/**
 * Base class for fast thread local variables.
 */
public abstract class FastThreadLocal {

    static class FastThreadLocalLocationIdentity extends LocationIdentity {
        @Override
        public boolean isImmutable() {
            return false;
        }
    }

    private final LocationIdentity locationIdentity;

    @Platforms(Platform.HOSTED_ONLY.class)
    FastThreadLocal() {
        this.locationIdentity = new FastThreadLocalLocationIdentity();
    }

    /**
     * Returns the {@link LocationIdentity} used for memory accesses performed by the {@code get}
     * and {@code set} methods of the subclasses.
     */
    public LocationIdentity getLocationIdentity() {
        return locationIdentity;
    }
}
